Current studies concentrate on comprehensive tests of hypothalamic-pituitary function and on the measurement and administration of specific behaviorally active peptides or peptide analogs. Major findings this year are: Drug-free bipolar patients show abnormalities in the osmoregulation of plasma arginine vasopressin (AVP) which are significantly correlated with levels of AVP in cerebrospinal fluid (CSF). Levels of CSF sometostatin are significantly reduced in unipolar and bipolar depressed patients compared to controls. Oxytocin (OT) is routinely present in the CSF of normal men and women in similar amounts, and the levels of CSF OT are systematically altered in subgroups of psychiatric patients with primary affective disorder and anorexia nervosa. In the intact and stalk-sectioned cynamologous macaque, peripheral administration of the newly-sequenced corticotropin releasing hormone (CRH) elicits the following physiological responses typically associated with the stress reaction in primates: cortisol secretion (with an ED50 between 0.1 Mu g/kg and 1.0 Mu g/kg), growth hormone and prolactin secretion, and tachycardia. The metabolic clearance rate of CRH in primates is exceedingly slow and its plasma half-time is longer than for any other known endogenous hypothalamic peptide.